When laid across objects in the midday sun, the bottom layer of silver reflected almost all the visible light that hit it: The film absorbed only about 4% of incoming photons. At the same time, the film sucked heat out of whatever surface it was sitting on and radiated that energy at a mid-IR frequency of 10 micrometers. Because few air molecules absorb IR at that frequency, the radiation drifts into empty space without warming the air or the surrounding materials, causing the objects below to cool by as much as 10°C. Just as important, Yin notes that the new film can be made in a roll-to-roll setup for a cost of only $0.25 to $0.50 per square meter.
“This is very nice work demonstrating a pathway toward large-scale applications of the concept of radiative cooling,” says Fan, who did not work on the current project. Yin says that he and his colleagues are already working on one such application, chilling water that could then be used to cool buildings and other large structures. That could be particularly useful in electricity-generating power plants, where cooling water even a few degrees can increase energy production efficiency by a percentage point or two, a “big gain,” Yin says. And without the silver backing, he adds, the plastic film could also increase the power generation from solar cells, which operate more efficiently at lower temperatures.
http://www.sciencemag.org/news/2017/02/cheap-plastic-film-cools-whatever-it-touches-10-c
Yes, it might be able to do that, but it depends upon the surface area of the cooling water lake or the flowrate of the river. Seaside plants can go down deep and get cold seawater year-round, but if a lake and/or the condenser was not sized correctly, that might help if it can cool the water fast enough. I work in the nuclear industry and my main job is figuring out how to maximize MW production. Comanche Peak, where I started, had a lake that was only about 2/3 the necessary surface area for the heat dumped into it, and in late summer, I saw inlet temperatures as high as 103F. The plant was designed for a maximum of 95F, and the losses increased dramatically after 100F. The condenser really needed to be about 15% bigger given the constraints of the terrain limited Squaw Creek Lake to the size it was built to. It probably would take covering the entire lake with this film to make a difference, and then it would be necessary only in the summer (Texas summer April-November). Violent thunderstorms would probably rip it to shreds several times a year.
The Dresden plant is cooled by both the Illinois River and a small shallow lake built out of old strip mines. We used to have to cut back on power production to keep from exceeding the maximum discharge temperature to the river until one guy had the brilliant idea to put forced draft cooling towers on the canals that routed discharged cooling water through the lake before it went to the river (it took 3 days to go through the lake before it was discharged into the river). That gave enough of a cooling boost to keep from backing off on power for most summers. Again, it would take a LOT of the film to cover the entire lake and it would have to be taken up before winter hit and it was ripped to pieces by snowstorms, and if the water gets too cold, then you lose efficiency too.
Plants like Seabrook, Diablo Canyon, or Turkey Point can get far enough out to tap deep cold seawater and usually do not see much variation in circ water inlet temperature, and again radiative cooling works too slowly to just out this film over the water discharge canal, the hot water simply moves too fast to get any benefit.
I've been seeing these pie-in-the-sky lab products touted as the next engineering miracle since I graduated engineering school in 1979. Show me it works reliably long term before I consent to using any of my money on it, and even then, it better have a very good payback period.
